Process of obtaining sodium sulfite.



UNITED STATES.

iatented November 3, 1903. PATENT OFFICE.

HERBERT. 1i. WING, or New BRIGHTON, NEW YORK.

PRooEss or OBTAlNlNG SODIUM SULFITE.

SPECIFICATION formingpart of Letters Patent no. 743,209, dated November 3, 1905s.

Application filed April 2, 1902. Serial No. 101,043 (N0 specimens.)

To all whom it may concern:

Be it known that I, HERBERT H. WING, a citizen of the United States of America, and a resident of New Brighton,Richmond county, State of New York, have invented certain new and useful Improvements in Processes of Obtaining Sodium Sulfite, of which the following is a specification.

The object of my invention is to produce sodium sulfite preferablyby the treatment of a sulfid product which is produced in a process for the production of nickel and copper, thereby incidentally improving said process. In the separation of nickel from copper according to Patents Nos. 489,574, 489,575, and 489,576, granted January 10, 1893, the matte, containing principally copper and nickel sulfids,is smelted with a sulfate of soda and coke. The fluid product is then run into slag-pots, where it cools. dumped out of the slag-pot and broken up, it is found that the nickel compounds of the mass have mostly settled in the bottom, while the copper, iron, and silica compounds have mostlyrisen to the top,and that there is quite a distinct line of separation between the socalled tops and bottoms. The tops, moreover, contain the greater part of the sodium sulfid,which results from the reduction of the sulfate by the coke, the proportion of the same being about twenty per cent. in some instances. The tops are smelted and then calcined, whereby the sulfur in the sulfids of copper and iron contained in the same is mostly driven 0E as sulfur dioxid gas, which being too dilute for the purpose of making sulfuric acid has to be thrown away, thereby often causing a nuisance. I have found that when the tops are finely ground, preferably in water and avoiding the presence of air as much as possible,and then heated in water to the boiling-point or higher and at the same time agitated the greater part of the soda contained in the mixed sulfid product will pass into solution as sodium sulfid and as caustic soda. material has taken place either before or during the grinding or leaching, then there appears to be some sulfite and hyposulfite in the liquid; -but with care this will be so small as to be inappreciable. In order to obtain the soda entirely as caustic soda and at the same When the solid mass is If any oxidation of the time to obtain it in one operation, a certain proportion of copper oxid is added to the mixed sulfid product, so that the sodium sul .fid as fast as it is,dissolved out of the mixed sulfid product is converted into caustic soda,

while the copper oxid is converted into sulfid and is then precipitated and mixed with copper and iron sulfid remaining as the insoluble residue after dissolving out the soda products. formed in an iron apparatus in which the con tents can be continuously agitated and heated. If the apparatus is made in the form of a tubemill, the grinding can also be accomplished at the same time the leaching is done, and thus the soda obtained as caustic soda in a single operation. The insoluble residue is then preferablyseparated from the solution of caustic soda by any well-known means, such as filtration, and then the waste sulfur gases given off in the calcination of the insoluble residue previously mentioned are then preferably washed or otherwise cleaned of the dust they may contain and are then brought into contact with the solution of caustic soda,

whereby there is produced a solution of sodium sulfite. This solution is then evaporated and cooled, thereby crystallizing out the sodium sulfite, which is then separated from the motherliquor. Thus beside utilizing the soda compounds produced in the separation of the nickel and copper in the matte by dissolving out the soda com pounds-the subsequent calcination of the tops referred to-that operation is more easily and cheaply accomplished, as the soda compounds when they are not leached out tend to fuse and retard the calcination, and by utilizing the fumes from such calcination a nuisance is avoided, while at the same time a valuable by-product is produced. The copper oxid added to the mixed sulfid product is preferably obtained by using a portion of the calcined residue, and only such amount is used as is required to convert the sodium sulfid obtained into caustic. If the copper oxid is not added to the mixed sulfids before leaching out, the liquor thus obtained containing some of the soda as sulfid is then heated and agitated with copper oxid, the sodium sulfid in the liquor will be converted into caustic and the liquor will contain substantially only caustic soda;

This operation is preferably perbut this plan requires two operations in place of the one above described.

While I have described my process as applied to utilizing the soda and sulfur fumes obtained from the tops in a nickel process of the character of that above referred to, the bottoms also contain soda compounds, which can be leached out and then converted into caustic soda and then converted into sulfite of soda. Also any matte can be smelted with sulfate of soda and coke and the resultant mixed sulfid product used to obtain caustic soda and sulfur fumes which when combined will produce sulfite of soda. I also do not wish to limit myself to the use of a neutral sulfate of soda known as salt cake for smelting, but would also use the acid sulfate known as niter cake, the expression used in the claims, a sulfate, being intended to include either one.

I have preferred to refer to the sulfid product as beinga mixed sulfid product, as it has not been satisfactorily determined whether the sulfids of the metals and sodium have formed a definite chemical combination or whether they only exist as a physical mixture. While it is probable that some of the iron forms a double sulfid with the soda, it has not been determined whether the copper or nickel does or does not.

In order to obtain the solution of caustic soda as strong as possible, it is desirable to first leach the mixed sulfid product with a dilute liquor obtained at a previous leaching, and thereby obtain a strong solution from the first treatment with it of the fresh mixed sulfid product. Then separate this liquor from the residue and then extract the remaining small amounts of soluble salts remaining in said residue with fresh water, thus obtaining the dilute liquor referred to. The strong caustic solution after purification from the usual impurities-such as small traces of iron, silica, &c.in the ordinary ways, for the production of the solution of sulfite of soda from which sodium sulfite crystals are obtained by evaporation and cooling. When purifying the caustic-soda solution by carbonating it to remove the small traces of iron which can be precipitated by this m ethod,a pat-tor thewhole of the caustic soda may be converted into carbonate or bicarbonate. In this case the liquid is then filtered or otherwise separated from the insoluble iron compounds which are thus precipitated and can then be used for treatment with the sulfur gases, as the sulfite can be as easily obtained from the carbonate as by use of the hydrate. When purifying the caustic-soda solution by means of blowing air through it, the small amount of carbonate thus formed from the CO gas in the air will, as above stated, have no injurious action on the production of the sulfite.

By the word leaching as used in this specification I do not wish to limit myself to any special temperature; but the same may take place at any temperature which from time to time may be found suitable or neces= sary, according to the character of the sulfite product to be leached.

I claim as my inventionl. The herein-described process of obtaining sulfite of soda which consists in smelting a matte with a'sulfate of soda and carbon, whereby a mixed sulfid product is obtained, then cooling it, then grinding, leaching and agitating it in the presence of copper oxid, whereby substantially all of the soda contained in said mixed sulfid product is obtained in solution as caustic soda, then separating said solution from the insoluble residue and then bringing gases containing sulfur dioxid into contact with said solution of canstic soda whereby sulfite of soda is produced.

2. The herein-described process of obtaining sulfite of soda which consists in smelting a matte'with a sulfate of soda and carbon, whereby a mixed sulfid product is obtained, then cooling it, then grinding, leaching and agitating it in the presence of copper oxid, whereby substantially all of the soda contained in said mixed sulfid product is obtained in solution as caustic soda, then separating said solution from the insoluble residue and then bringing gases containing sulfur dioxid into contact with said solution, whereby sulfite of soda is produced, and then separating said sulfite of soda from the liquor in which it was produced.

3. The herein-described process of obtaining sulfite of soda which consists in smelting a copper-nickel matte with a sulfate of soda and carbon, running the mixed sulfid prodnot thus obtained while molten into suitable receptacles, then after cooling and solidification of said product, separating the tops from the bottoms, then grinding, leaching and agitating said tops in the presence of copper oxid, whereby substantially all of the soda contained in said tops is obtained in solution as caustic soda, then separating said solution from the insoluble residue, and then bringing gases containing sulfur dioxid into contact with said solution, whereby sulfite of soda is produced.

4. The herein-described process of obtaining sulfite of soda which consists in smelting a copper-nickel matte with a sulfate of soda and carbon, running the mixed sulfid product thus obtained while molten into suitable receptacles, then after cooling and solidification of said product, separating the tops from the bottoms, then grinding, leaching and agitating said tops in the presence of copper oxid, whereby substantially all of the soda contained in said tops is obtained in solution as caustic soda, then separating said solution from the insoluble residue, then bringing gases containing sulfur dioxid into contact with said solution, whereby sulfiteof soda is produced, and then separating said sulfite of soda from the liquor in which it was produced.

.5. The herein-described process of obtain- IIO ing sulfite of soda which consists in smelting a matte with a sulfate of soda and carbon, whereby a mixed sulfid product is obtained, then cooling it, then grinding, leaching and agitating it, then separating the liquor from the insoluble residue, then adding copper oxid to said liquor, agitating same, whereby substantially all of the soda contained in said mixed sulfid product is obtained in solution as caustic soda, then separating said solution from the insoluble residue, and then bringing gases containing sulfur dioxid into contact with said solution, whereby sulfite of soda is produced.

-6. The herein-described process of obtaining sulfite of soda which consists in smelting a matte with a sulfate of soda and carbon,

whereby a mixed sulfid product is obtained, then cooling it, then grinding, leaching, and agitating it, then separating the liquor from the insoluble residue, then adding copper oxid to said liquor, agitating same, whereby substantially all of the soda contained in said mixed sulfid product is obtained in solution as caustic soda, then separating said solution from the insoluble residue, then bringing gases containing-sulfur dioxid into contact with said solution, whereby sulfite of soda is produced and then separating said sulfite of soda from the liquor in which it was produced.

7. The herein-described process of obtaining sulfite of soda which consists in smelting a copper-nickel matte with a sulfate of soda and carbon, running the mixed sulfid product thus obtained while molten into suitable receptacles, then after cooling and solidification of said product, separating the tops from the bottoms, then grinding, leaching and agitating said tops, then separating the liquor from the residue, then adding cop per oxid to said liquor, agitating same,whereby substantially all of the soda contained in said tops is obtained in solution as caustic soda, then separating the solution from the insoluble resid us and then bringing gases containing sulfur dioxid into contact with said solution, whereby sulfite of soda is produced.

8. The herein-described process of obtaining sulfite of soda which consists in smelting a copper-nickel matte with a sulfate of soda and carbon, running the mixed sulfid product thus obtained while molten into suitable receptacles, then after cooling and solidification of said product, separating the tops from the bottoms, then grinding, leaching and agitating said tops, then separating the liquor from the residue, then adding copper oxid to said liquor, agitating same,whereby substantially all of the soda contained in said tops is obtained in solution as caustic soda, then separating the solution from the insoluble residue, then bringing gases containing sulfur dioxid into contact with said solution, whereby sulfite of soda is produced and then separating said sulfite of soda from the liquor in which it was produced.

9. The herein-described process of obtaining sulfite of soda which consists in smeltinga copper-nickel matte with a sulfate of soda and carbon, running the mixed sulfid product thus obtained while molten into suitable receptacles, then after cooling and solidification of said product, separating the tops from the bottoms, then separately grinding, leaching and agitating said tops and bottoms, then separating the liquor from the residue contained in each, then adding copper oxid to said liquor, agitating same, whereby substantially all of the soda contained in said tops and bottoms is obtained in solution as caustic soda, then separating said solution from the insoluble residue, contained in each, and then bringing gases containing sulfur dioxid into contact with said solution, whereby sulfite of soda is produced.

10. The herein-described process of obtaining sulfite of soda which consists in smelting a copper-nickel matte with a sulfate of soda and carbon, running the mixed sulfid product thus obtained while molten into suitable receptacles, then after cooling and solidification of said product, separating the tops from the bottoms, then separately grinding, leaching and agitating said tops and bottoms, then separating the liquor from the residue contained in each, then adding copper oxid to said liquor, agitating same, whereby substantially all of the soda contained in said tops and bottoms is obtained in solution as caustic soda, then separating said solutions from the insoluble residue contained in each, then bringing gases containing sulfur dioxid into contact with said solution, whereby sulfite of soda is pro duced and then separating said sulfite of soda from the liquor in which it was produced.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of two witnesses, this 21st day of March, 1902.

HERBERT H. WING.

Witnesses:

WILLIAM PARKER BUTLER, JOHN FRENCH. 

